It comes with an assortment of springs, sway bars, and shock pistons. Those will pretty much get the handling where you want it, short of a diff fluid change. The car is pretty tough, but you can't go wrong keeping a set of spare suspension arms, and a variety of pinion gears. Also, the Kyosho nylon spur gear is a popular mod, makes the car allot more quiet. There's one at my track, and the difference is night and day!
It's a pretty durable car, you aren't likely to brake anything. Just bring the stuff you need to dial it to your situation.